A hybrid vehicle and an electric vehicle are mounted with a power conversion device including a plurality of inverters for driving a motor. The inverter converts direct current power supplied from a battery into alternating current power to drive the motor, and conversely convers alternating current power regenerated by the motor into direct current power and stores the power in a power storage apparatus. Each inverter includes a semiconductor module having a power semiconductor device and controls on-off operation of the power semiconductor device to drive the motor.
Since an amount of heat generated from the power semiconductor device by on-off operation is extremely large, the semiconductor module is required to have a structure with high cooling performance.
For meeting the requirement, for example, Patent Literature 1 discloses a method of improving cooling performance by dissipating heat generated due to on-off operation of a semiconductor device from both sides of a semiconductor module.
When a plurality of the semiconductor modules shown in Patent Literature 1 are mounted on a power conversion device, for obtaining excellent heat dissipation in each of the semiconductor modules, it is necessary to narrow down a sectional area of a water path by providing a water path wall so as to be adjacent to a heat dissipation portion, thereby making a large volume of cooling water flow to the heat dissipation portion of a heat dissipation case. The need of providing each semiconductor module with a water path wall and providing a space between the water path wall and the heat dissipation portion so as to prevent an interference therebetween involves a problem of an increase in size of the power conversion device.
Additionally, the semiconductor module has a flange portion for the fixing to a flow path-forming body or the like, and a space for connecting the flow path-forming body and the flange portion might prevent reduction in size of the power conversion device.